1. Field of the Invention
The present invention relates to a stage apparatus that is suitably used for a semiconductor exposure apparatus, an inspection apparatus, or the like, and that positions an exposure original plate, an object to be exposed, or an object to be inspected, in a predetermined position. The present invention also relates to an exposure apparatus and a device manufacturing method.
2. Description of the Related Art
In a semiconductor manufacturing process, in a projection exposure apparatus in which a pattern of a reticle (or mask) serving as an original plate is projected and transferred onto a semiconductor (silicon) wafer serving as an exposure substrate, when the reticle pattern is projected and exposed onto the wafer, a reticle stage and/or a wafer stage, i.e., a stage apparatus, is used to move the reticle and the wafer with respect to the projection exposure system.
In such a stage apparatus, a drive reaction force occurring when driving the stage undesirably causes a reduction in accuracy of the stage. As a countermeasure against this problem, there is a method disclosed in Japanese Patent Laid-Open No. 11-190786, for example (see FIG. 15 in the present description).
As shown in FIG. 15, an X slider 30 and a Y slider 33, each serving as a wafer stage, are slidably supported on a stage surface plate 2 by an air slide (not shown), and when each of them receives an acceleration force, its reaction force acts on the stage surface plate 2. Because the stage surface plate 2 is slidably supported on a base surface plate 3 by an air slide (not shown), the stage surface plate 2 moves due to the reaction force, and no force acts on the base surface plate 3. That is, the stage surface plate 2 functions as a counter-mass with respect to the X slider and the Y slider, thereby canceling out the reaction force and preventing it from being transmitted to the outside.
When the X slider 30 or the Y slider 33 accelerates at a position deviated from the barycenter of the stage surface plate 2 in the X direction or the Y direction, a rotational force about the Z axis occurs. Also, when the barycenter of the X slider 30 or the Y slider 33 deviates from that of the stage surface plate 2 in the Z direction, rotational forces about the X axis and the Y axis occur. These rotational forces are undesirably transmitted to the base surface plate 3. As a countermeasure against this, the stage surface plate 2 is provided with counter rotors 4 rotating about the X axis and the Y axis, and also, a counter rotor (not shown) rotating about the Z axis, and each of these counter rotors 4 is rotated in synchronization with the occurrence of a respective one of the rotational forces to cancel out the rotational force.
As disclosed in Japanese Patent Laid-Open No. 11-190786, when the stage surface plate is supported as a counter-mass on the base surface plate by an air slide, there occurs the need to provide the air slide with a required degree of flatness over a wide region, so that it is difficult to enlarge the stage surface plate. However, a small stage surface plate, that is, a stage surface plate that is small in mass, would undesirably increase the moving amount required of the stage surface plate serving as a counter-mass, thereby increasing the region requiring a high degree of flatness in the base surface plate.
For this reason, when supporting the stage surface plate as a counter-mass on the base surface plate by an air slide, it is difficult to cancel out the stage drive reaction force to provide a high-accuracy stage apparatus.
On the other hand, when supporting the stage surface plate by rolling bearings of a linear motor guide (LM guide), or the like, instead of the air slide, an endurance problem occurs, and there is a concern that vibrations due to moving in and out of ball bearings can occur. Furthermore, either one of the linear motor guide and the air slide undesirably transmits vibrations in the Z direction to the stage, and hence, in this case, it is necessary to further provide a vibration isolating foundation for isolating the vibrations in the Z direction.